Insulator



sept. V9, 1924. 1 1,508,250

K. C. RANDALL INSULATOR Filed Dec. 14, 1918 //////////'I /l/ /l WITNESSES: INVENTOR Kar/ K. Randa# 'senza BY ATTORNEY Patented Sept. 9, 1924.

UNITED STATES- l 1,508,250 PATENT orrlcE.

KARL C. RANDALL, F YEIDG'rilWOOD PARK, PENNSYLVANIA, ASSIGNOR T0 'WEST'ING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 0F PENNSYL- 'VANIA.

INSULATOR.

v Application file-d December 14, 1918. Serial No. 266,720.

To all whom 'it may concern.'

Be it known that'I, KARL C. RANDALL, a citizen of the United States, and a resident of Edgewood Park, in the county of i Allegheny and State of Pennsylvania, have invented a new xand useful Improvement in Insulators, of which the following is a specification.

My invention relates to insulators for thc l0 support of bus-bars or other conductors and has for its object to provide a hollow insulator that, by `reason of having both its inner and outer surfaces conforming to the dielectric field or fields in which the surfaces 'are disposed, shall combine the features of maximum electrical and mechanical strength, simplicity of construction and economy in manufacture. i

As 4disclosed in Patent No. 1,129,520, rantedl to the Westinghouse Electric & fg. Company, February 23, 1915, upon an application filed by K. C. Randall, S. W. Farnsworth and C. LeCr. Fortescue, the concentration of potential stresses, in the, vi- -5 cinit of an insulator, may be avoided by shapingl thev insulator surfaces to conform to the dielectric field in which `it is disposed. I

Various devices embodying applications of the principles disclosed in the above patent have subsequently been roposed, prin- .cipally among which have een' suspension and-pintype insulators for high-potential transmission lines. These have usually comprised solid bodies or bodies so formed or related to each other that the necessity of having vinterior surfaces also conforming to the dielectric field has not heretofore existed. Certain protective barriers of uniform and minimum thickness have been vformed to simulate the surface of a single tube of force.

In practicing my invention, I provide a hollow pillar-type insulator, preferably of porcelain, for the support of bus-bars or other conductors and having relativelyA great mechanical strength, that conforms,

at both its inner and outer surfaces, to the i dielectric field'in which it is disposed. To permit the insulator to besecured to a switchboard, or other support, and, in order that it may support a bus-bar or bars, relatively rugged and extensive metal members are secured to its ends. This construction,

in consideration of the mechanical requirements, may or may not be conducive to the production of a uniformly diverging or converging dielectric ield, and in providing a hollow insulating structure having both its inner and outer surfaces conforming to separate and distinct tubes of force, the combined advantages of maximum'electrical and mechanical strength, simplicity "of construction, economy of manufacture, effectiveness in operation, and convenience in assembling, handling and shipping with lessened liability of damage thereto are obtained.

Ina co-pending application, Serial No. 266,704,filed Dec. 14, 1918, by` James M. Brown and assigned to the Westinghouse Electric & Mfg. Company, is` disclosed an insulator having a certain novel mechanical structure particularly adapt-ed for use in cooperation with an insulator embodying thev principles herein disclosed.

The single figure of the accompanying drawings'is a longitudinal sectional view,

v partially in elevation and as viewed in the direction of the axis of a `bus-bar, of an of which is shown, extend through the member? and have co-operating nuts 10 to secure the member 7 to a suitable support, not shown. A cushioning ring 11 of felt or other suitable material is disposed between the flanges 3 and 5. A preferably relatively-thin-walled metal member 12, of substantially cup-shape has its main body portionextending into one end of the membei' l and an outwardly-projecting flange 14 nested between the members 1 and 7 in a recess in the outer face of the latter member. The member 12 assists in -mechani cally reinforcing the member 1 against lateral stresses, serves as a positioning means therefor and by having an end face 15 disposed n the plane of the outer face of the j aiige' 5, assists thellatte'r in directing the dielectric field, in a manner' to be hereinafter explained.

Members l'and 17 engage the outer end of the member 1 on the outside and the inside, respectively, o'f'the flange. 2 `and are joined togetherl by bolts 18. A resilient Acushioning washe r ,19, of 'felt or other suitable material, is interposed between the' flange 2 andthe member 17'. An interiorlythreaded centrally-disposed tubular portion 20, of the member 16, supports'an adjustable screw-threaded stud 21 thatmay. be locked lin adjusted position by a.set 'screw 22 extending through the portion 20. A pair of complemental clamplng4 members 23, -between which a bus-bar 24 is rigidly .clamped 'Y by bolts 25" and nuts outer end of the stud 21.

26, is secured to the .Adjusting Screw-bolts 28,

permit the rigid and accuratecorre ation of the insulator members, regardless of irregularities in the -members and of any deviation from true parallel in the relation between thepla'nes of thebus-bar 24 and the member I. The members 16` and 17 are formed to present a s ingle spheroidal surface 27, except' as it is intercepted by the Walls of the member 1, toward the members 4 and 12 that,` together, present the fiat surface 15 bounded by rounded outer edges provided by the flange 5. This relation of the surfaces 27 and D15 tends to uniformly direct the dielectric eld, as indicated by dotted considerations only, it is obvious that violent and destructive electrical stresses might `obtain. Further,.as explained in the above mentioned patent, an insulator constructed in accordance with these principles utilizes the? full insulating .value of air in addition Y to effecting relatlvely greatsimplification and economy of construction therein.

. While 'I have shown and described a particular form of myiinvention, changes may be effected therein withoutdeparting the Yspirit andsco e there f, ias set forth in the a pended claims.

'I c aim as my invention:

. L-An insulator comprising a hollow insulating member having a perimetral trans- 'verse'end ange, ametal terminal member a the insuonly one of which is shown,lextend through the member v16 to the outer'surface ofthe flan e 2 and with each other to clamp a portion of the -v insulating member therebetween and each definitely directing the electric .field-of the insulator relative to said surfaces and to the other terminal member. l

3.l In an insulator, the combination with a hollow insulating member, of terminal structures therefor, one of which comprises metal members dis osed on the inside and outside of said holl respectively, and co-operating with each other, to definitely direct the electric field of the insulator with respect to the other terminal structure and to mechanically clamp a portion of the insulator between them. t

4. In an insulator, the combination with an insulating member, vof terminal structures therefor, one of which comprises a pair of metal members co-operating with each other to readily removably'mechanically clamp a portion of the insulating member between them and to definitely direct the electric field of the insulator with respect to the other terminal structure.

5. In combination, a pair of terminal structures, one of whichcomprises' a pair of metal members co-operating with each other to readily-removably mechanically clamp a portion of an insulating member between them and to definitely direct an electric field relative to the other terminal structure, and a hollow insulating memberhaving an open en'd portion clamped lbetween said metal members and extending in conformityy to said field to the other terminal structure.

i 6. An insulator vcomprising a hollow i n sulating member and terminal structures at each end thereof, one of said terminal strucow insulating member, y

tures embodying a pair of metal members disposed on the inside and outside, 4respectively, of the insulator co-operating' to mechanically clam a portion of the insulate ing member there etweenfandv to definitely direct the electrostatic eldof the insulator relative to both the inner and outer longi- V-t'udinal surfaces of the'insulating member andto the other, terminal member.' i 'In testimony .whereof, I have hereunto subscribedgmy name this 30th day of Nov., A1918.f f

KARL o. RANDALL. 

